Immunomodulatory Responses of Two Synthetic Peptides against Salmonella Typhimurium Infection

In vitro assays of phagocytic activity showed that the peptide Pin2[G] stimulates phagocytosis in BMDM cells from 0.15 to 1.25 mu g/mL, and in RAW 264.7 cells at 0.31 mu g/mL. In the same way, the peptide FA1 induced phagocytosis in BMDM cells from 1.17 to 4.69 mu g/mL and in RAW 264.7 cells at 150 mu g/mL. Cytokine profiles of uninfected RAW 264.7 showed that Pin2[G] increased liberation TNF (from 1.25 to 10 mu g/mL) and MCP-1 (10 mu g/mL), and FA1 also increased the release of TNF (from 18.75 to 75 mu g/mL) but did not increase the liberation of MCP-1. In RAW 264.7 macrophages infected with Salmonella enterica serovar Typhimurium, the expression of TNF increases with Pin2[G] (1.25-10 mu g/mL) or FA1 (18.75-75 mu g/mL). In these cells, FA1 also increases the expression of IL-12p70, IL-10 and IFN-gamma when applied at concentrations of 37.5, 75 and 150 mu g/mL, respectively. On the other hand, stimulation with 1.25 and 10 mu g/mL of Pin2[G] promotes the expression of MCP-1 and IL-12p70, respectively. Finally, peptides treatment did not resolve murine gastric infection, but improves their physical condition. Cytokine profiles showed that FA1 reduces IFN-gamma and MCP-1 but increases IL-10, while Pin2[G] reduces IFN-gamma but increases the liberation of IL-6 and IL-12p70. This data suggests a promising activity of FA1 and Pin2[G] as immunomodulators of gastric infections in S. Typhimurium.

Automated summary

The peptides Pin2[G] and FA1 were found to stimulate phagocytosis in in vitro assays, impacting cytokine release and improving the physical condition of mice with gastric infections caused by S. Typhimurium.